Lucas Marine Semi-Synthetic SAE 20W-50 Racing Oil is fortified with a unique additive package containing high levels of zinc, molybdenum and phosphorus, which provides a tougher, thicker additive film for maximum protection even under the most severe conditions. It lowers oil temperatures, extends oil life and minimizes metal fatigue. It improves the film strength between the cylinder wall and piston rings and slows oil burning and improves pressure in worn engines. It has excellent cold temperature properties and stands up to high operating temperatures. Lucas Marine Semi-Synthetic SAE 20W-50 is compatible with methanol and all racing fuels. It is compatible with synthetic and non-synthetic oils. Lucas Marine Semi-Synthetic SAE 20W-50 Racing Oil is designed for use in high performance boats requiring the ultimate protection. Not recommended for passenger car use.